Apparatus for fusing metals



, m I 1 l 3 ii Q JL Nov. 26, 1935. J. A. ZUBLIN 2,022,171

APPARATUS FOR FUSING METALS Original Filed Aug. 6, 1954 JOHN A. ZUBLININVENTOR ATTORN EY UNITED STATES PATENT OFFICE APPARATUS FOR. FUSINGMETALS John A. Zublin, Los Angeles, Calif.

Original application August 6, 1934, Serial No.

738,684. Divided and this application December 22, 1934, Serial No.758,774

9 Claims.

The present invention has to do with apparatus for fusing metals toproduce a relatively uniform body from constituents that do not readilymix or dissolve one in another. As a specific example of the invention,there is shown apparatus adapted to making alloy welding rods, since theapparatus has been developed with this end in view; but it is to beunderstood that the invention in its broader aspects is not limited tothis specific device or this particular use, for it may be embodied indevices adapted to other uses.

It has been common practice to melt metals to.

efiect a solution or mixing of them while in the liquid state, but suchpractice is not adapted to those metals which do not mix when liquid,such as iron and copper which are very sparingly soluble in each otherand, at certain temperatures, immiscible. Another example is lead andzinc. When these first two metals are subjected to the conventionalmethods of melting in a crucible and then pouring into a mould, there isnecessarily sufiicient elapsed time for the metals to separate, and thecasting contains the undissolved copper in a few large segregations thatresult in a decidedly non-uniform product.

I have found, however, that if the constituents, after being intimatelymixed, are melted and subsequently cooled so rapidly that separationcannot occur, the resulting product is substantially uniform andcontains the elements in quantities in excess of the amounts that can bemutually dissolved. The total time involved is very short so that themetals are not fluid long enough to separate; also losses by oxidationand vaporization are kept low by reducing the duration of exposure tohigh temperatures.

The present invention has as a general object the provision of apparatusfor rapidly fusing together metals which do not easily mix or dissolvein one another and for rapidly congealing these fused metals to form asolid unitary body of substantially uniform composition and distributionof the constituent metals, at least one of the metals being present inquantities in excess of the amounts that can be dissolved in theremaining metals.

Another object of the invention is to provide means in which the metalsmay be fused but which also has mould characteristics so that there isno time required for the transfer of the molten material from a crucibleto a mould.

Another object is to provide apparatus which is not critical in itsoperation as regards the state of division or the particle size of thecharge to be melted, but which can be operated successfully with afinely powdered charge or with onecomprising relatively large particles,or with a mixture of large and small grains.

A further object is to provide a device with which the quantity,intensity, and duration of 5 heating can be readily controlled accordingto the quantity and physical characteristics of the charge to be melted,in order to secure proper rate of melting, time of liquefication, andtemperature of melting, and in which the heat can be locally l0concentrated to efiect fusion of substances of high melting point.

These objects are attained in an apparatus embodying my invention, thatcomprises a mould, in the shape of the final product, adapted to receivethe charge of mixed metals. At least one wall of the mould is anelectrical conductor or electrode, and a second electrode is adapted formovement into arcing relation with the mould electrode so that the arebetween them passes through the substance to be fused, the twoelectrodes being capable of relative movement so that the arc may bemoved on away from the molten charge to progressively fuse the remainderof the charge.

The final product contains the undissolved excess of a metal in smallparticles dispersed throughout the remainder of the metals, similar tobeing embedded in a matrix. In this respect the product is similar to asintered product, but the process is more nearly true melting since all30 constituents will normally melt at the temperatures available, exceptpossibly in case of difcultly fusible substance such as tungsten carbideis used with a metal of much lower melting point and it is not necessaryor desirable to fully melt 35 the constituent of highest fusion point.

My improved method of fusing metals is set forth with greater detail inmy co-pending application entitled Method and apparatus for fusingmetals, Ser. No. 738,684, filed August 6, 40 1934, of which the presentapplication is a division and in which the process is claimed; and forfurther details as to the composition of a typical product, referencemay be had to my co- 45 pending application Alloy and method of makingsame, Ser. No. 738,683, filed August 6, 1934.

How these and other objects and advantages of my invention are attainedwill be more easily understood from the following description of a 5()preferred and typical form of apparatus, and the annexed drawing, inwhich:

Fig. 1 is an end view, with portions broken away, of a deviceconstructed in accord with my invention; 55

Fig. 2 is a longitudinal vertical section on line 2--2 of Fig. 1;

Fig. 3 is a diagrammatic plan of a revolving table carrying a pluralityof the units illustrated in Fig. 1; and

Fig. 4 is a diagrammatic perspective of a variational form of apparatus.

Referring now to Fig. 1, a table or any suitable supporting means isindicated at I upon which rests base plate I2 of a mould unit. Attachedto the base plate in any suitable way is a plurality of triangularblocks arranged in opposed pairs I3 and I4 so that the upper oppositelyinclined faces of the pairs present a general V- formation upon whichrests the cylindrical electrode generally indicated at I5. The electrodeassembly I5 comprises a central cylindrical member I6 and a pair ofdiscs I! carried one at each end of cylinder I6 and held in place bybolt I8 as illustrated in Fig. 2. If desired, discs I! can beformedintegrally with cylinder I5 as terminal flanges.

A pair of bricks 20 are so placed that their inner longitudinal edgesrest upon the top of cylinder I6 and present opposed faces 20a spaced atshort distance apart. The bricks are of the same length as cylinder I6and fit in between discs II. In this way, the bricks and electrodeassembly I5 form an elongate mould or charge receiving space 22 on topof cylinder I6, of which mould, faces 200. form the side walls, cylinderI6 forms the bottom wall, and discs I! form the end walls. Since thecharge is melted while in space 22, this space is in the nature of acombined crucible and mould to shape the final product. The outer edgesof the bricks are supported by posts 24 threaded into standards 25secured to base I2. Base I2 and the lower portions of standards 25 arecounter-bored as at 26 to receive posts 24 so that the latter may beadjusted vertically by simple rotation to properly position bricks 20.In this way the bricks may be suitably adjusted to any size of cylinderI6, and the bricks may be moved toward or away from each other to alterthe size and shape of space 22 so that the mould formed thereby will beof the desired shape.

For reasons that will be more evident, it is preferred that cylinder I6be of electrically conductive material, and for this purpose carbon ispreferred since it has a relatively high melting point. Bricks 20 may beof any suitable material, and it is preferred that they be ofelectrically non-conductive material since during the appli- 1 cation ofthe electric arc, to be described later,

the arc is likely to short across to the bricks rather than pass throughthe charge in space 22 and then to electrode I5. As it is sufficientthat only one wall of the mould be an electrode, the

' bricks are preferably of some refractory material which is not likelyto combine with the materials that are fused.

Although the electrode I5 may have a cross section other than circular,a generally circular cross section is preferred because, after thesurface of cylinder I6 has become rough and pitted from use, a selectednew surface may be brought into the top position to act as the mouldwall by simply rotating the entire electrode, and, being circular, itwill rest on blocks I3 and I4 equally Well in any position. Furthermore,the periphery of cylinder I6 may be provided with indentations or otherconfigurations designed to shape the final product, and when theelectrode is circular or approximately so it is easily possible to bringselected portions of the electrode into operative position by rotatablyadjusting it on its supports.

A movable electrode is provided in the form of carbon pencil 28 held inclamp 29 on handle 30 so that it may be grasped by an operator and 5moved lengthwise of mould 22. Electrode 28 is an ordinary carbon pencilof relatively small area as compared with the total area of space 22 sothat the are passing between the two electrodes is concentrated in asmall space and the total heat of the electric current is localized. Aswill be understood, it is not necessary that this upper electrode bemanually movable, for mechanical control means may be used. Or thepencil may be stationary and the lower electrode movable since anyarrangement which secures relative movement between the two electrodeswill provide an arc which moves along the entire mould.

The electrical power is direct current supplied from any suitable sourceby negative lead 32 attached to electrode 28 and positive lead 33attached to binding post 34 on base plate I2, the current passing toelectrode I5 through wedges I3 and I4.

Any suitable material may be placed within mould 22 depending upon thepurpose for which the apparatus is used; but in the practice of formingwelding rods this material is a mixture of powdered metals which arefused and then congealed to form a solid rod. Since the exactcomposition of the rod is immaterial to the present invention, itsconstituents will not be further described, although reference may behad to my companion application, Alloy and method of making same,mentioned above, for a typical 35,

alloy composition.

It has been found preferable to comminute the metals so that theindividual grains are, preferably, generally uniform in size and aboutas large as will pass through a 20-mesh screen. grain size is preferredsince a relatively uniform charge is attained by thoroughly intermixingthe several constituents; but this particle size is not limitative, forthe device will also operate with a mixture having a wide range of largeand small particles. Also a charge may be used that comprises one ormore wires or rods laid lengthwise of space 22, since the deviceoperates satisfactorily over a wide range of particle sizes.

After first thoroughly and intimately mixing the constituents by anysuitable means, a proper amount of the mixture is introduced into themould. With electrode 28, an arc is then struck at one end of the mould,the current passing through the mixture to electrode I 5. The intenseheat of the arc rapidly melts the powdered materials beneath pencil28,,and as rapidly as the material melts in one spot the arc is movedaway from the molt-en charge and over unmelted charge so that the entirecharge is progressively melted from one end to the other. The masses ofbricks 2i! and electrode I5 are relatively large and are not appreciablyheated. during the short exposure to the arc. Consequently the heatflows rapidly out of the fused substance into the cooler mould wallswhere it is dissipated. In this way the fused substance is quicklycongealed and chilled to relatively low temperature. Thus there are inthe mould at the same time three stages of the product: the congealedsolid 36 behind the electrode, the fused substance 37 beneath theelectrode, and unmelted mixture 38 ahead which is being progressivelyexposed to the arc.

Rapid cooling of the charge immediately following the fusion is madepossible by progres- This 40 sively exposing the unmelted chargedirectly to the arc, for in this way the previously melted material isnot used to transmit heat to charge as yet unmelted, as is the case inconventional furnaces and crucibles. In the short time that the liquidstate is maintained, constituents which readily mix and dissolve in oneanother will become thoroughly intermingled, but if the liquid state ismaintained for any appreciable time, those constituents which do not mixreadily will tend to separate from the remainder of the metals and willform large aggregations causing a non-uniformity in the final product.By quickly moving the are away from any point just as fusion occurs, andthen quickly chilling the fused substance, the metals freeze while stilluniformly intermingled and before segregation takes place, thusresulting in a relatively uniform final structure. Furthermore, thetotal duration of exposure at high temperatures has been reduced to aminimum so that loss of elements from oxidation or vaporization willalso be held to a minimum.

For the melting operation, there is used very intense localized heat.The electric arc is preferred to the acetylene torch because there is noblast of gas to blow away the powder and it is possible to get a greaterintensity of heat. As an example, good results have been obtained withcurrents of 400-600 amperes at a potential of 30 volts. The aretemperature is in the neighborhood of 3,000 degrees centigrade, which iswell above the melting point, or in many instances even the boilingpoint, of most substances which may be fused in the mould. This currentprovides an arc having such a large quantity of heat as to almostinstantaneously melt the mixture, regardless of variations in the sizeor melting point of the individual pa ticles. The combination of hightemperature and high heat output make negligible the difference in timeof melting between large and small pieces, or ones with high and lowmelting points.

In practice, the electrode can be moved substantially continuously alongthe mould. When electrode 28 is hand operated, the rate of movement maynot be uniform, or the operator may temporarily move the electrodebackwards, but in general its movement may be characterized as beingcontinuously forward, away from the molten portion of the charge, toprogressively expose unmelted portions of the charge to the arc. Therate of movement will depend on the energy output of the arc, the massof charge per unit length of the mould, and, to some extent, thefusibility of the charge. For example, other factors remaining constant,the electrode speed will vary with the spacing of faces 20a as thatcontrols the size of rod produced and hence the weight of charge perinch to be melted. By proper regulation of these inter-related factors,control is exercised over the rate of melting, the time ofliquefication, and the temperature of the melt.

The electric energy is used very efficiently for radiation losses aresmall, the time during which the metal is maintained liquid is short,and there is no large mass of furnace, crucible, or mould to heat. As aresult, nearly all the heat supplied is used to melt the charge.

Fig. 3 illustrates a device in which a plurality of mould units such ashave been already described are placed upon a movable support so thatthey may be successively moved past a given point. It has been foundadvantageous to mount a plurality of these units 40 on a central table42 which rotates about a vertical spindle 43. In this case, the operatoruses a single movable electrode 28 but is stationed at one place so thatthe electrode has only a predetermined 5 range of movement. By rotatingtable 42, successive mould units may be placed in front of him withineasy reach and when the fusing operation has been completed in each unitit may then be moved on to a successive point where a sec- 0nd operatorcan remove the finished welding rod. and prepare the mould to receiveanother charge of mixture. Obviously, these mould units need not beplaced upon a circular table but may be placed upon any suitable movingmember which will pass them before a particular point; and the movableelectrode may be machine operated to move only longitudinally of themould, after the mould has been moved into position beneath theelectrode.

Fig. 4 illustrates diagrammatically a variational form of apparatus. Inthis form, the upper electrode 45 is mounted in a stationary bracket 46so that it is fixed in position. The mould is formed by a cavity in ablock of carbon 48 which rests upon a moving member 49 adapted to passblock 48 past electrode 45 so that the cavity therein moveslongitudinally relative to the upper electrode. In this construction,all the mould walls are formed by an electrode which happens to be themovable one.

Obviously, the cavity in block 48 forming the mould or materialreceiving space may be of any suitable shape or configuration accordingto the shape of the final product. Also, the shape of both electrodesand the nature of the relative movement between them may be changed toconform suitably to moulds having shapes other than herein illustrated.

In the event that it is desired to preheat the mixture, this may be doneby so attaching the power connection to the mould electrode that thecurrent will pass through the unfused substance before the electrode isactually over it. For example, in Fig. 4 the lower electrode is movingtoward the left as indicated by arrow so that the relative movement ofstationary electrode 45 is toward the right as indicated by arrow 5|,and to preheat powdered material 52 power connection 33 is attached at53 to the right hand 50 end of the mould which is at a point removedfrom the upper electrode in the direction of the latters movementrelative to the mould. The smaller the cross section of the lowerelectrode the greater the heating eifect will be, since the 55resistance, and consequently the temperature, of the electrode isinversely proportional to its cross sectional area. Under somecircumstances it may be desired to prevent quick chilling by postheatingthe molten charge 55; and this can be accomplished either by reversingthe relative direction of movement of electrodes 45 and 48 or byattaching the power connection to the opposite or left hand end ofelectrode 48, so that the electric lead to the lower electrode is at apoint removed from the upper electrode in the direction opposite to thelatters movement relative to the mould.

Having described the improved method and preferred forms of apparatusembodying my invention, it will be realized that the disclosure of thedrawing and specification is to be considered as illustrative of ratherthan restrictive upon the broader claims appended hereto, for variouschanges may be made by those skilled in the art without departing fromscope'of my invention. 7 I

I claim'as my invention:

1.-In adevice of the-character described, a mould adaptedto receive acharge of a fusible substance, the mould "comprising a base, a generallycylindrical electrode mounted on the base, a pair of bricks with theirinner edges resting on the top of the cylinder to provide opposed facesthat with the cylinder form a space adapted to receive the charge, andsupports for the outer edges of the bricks; a second electrode movablerelative to the mould to progressively fuse the charge; and electricalpower connections to the electrodes.

2. In a device of the character described, a mould adapted to receive acharge of a fusible substance, the mould comprising a base, a generallycylindrical electrode mounted on the base for adjustment to selectedrotational positions, a pair of bricks with their inner edges resting onthe top of the cylinder to provide opposed faces that with the cylinderform a space adapted to receive the charge, and supports for the outeredges of the bricks; a second electrode movable relative to the mould toprogressively fuse the charge; and electrical power connections to theelectrodes.

3. In a rod forming device of the character described, a mould adaptedto receive a charge of a fusible substance and comprising a centrallongitudinally disposed electrode, detachable members of non-conductiverefractory material resting upon the electrode to provide opposed wallsthat with the electrode form a relatively long and narrowcharge-receiving space extending longitudinally of the electrode, andmeans supporting the refractory members in place; and a second electrodemovable longitudinally of the first electrode to progressively melt thecharge.

4. In a rod forming device of the character described, a mould adaptedto receive a charge of a fusible substance and comprising a base, acentral longitudinally disposed electrode mounted on the base, membersof non-conductive refractory material providing downwardly and inwardlysloping walls which with the electrode form a the spirit and relativelylong and narrow charge-receiving space extending longitudinally of theelectrode, and means supporting the refractory members in place; and asecond electrode movable-longitudinally of the first electrode toprogressively fuse the charge. I

5. In a rod forming device -of the character described, a mould adaptedto receive a charge of a fusible substance and comprising a base, acentral longitudinally disposed electrode mounted on the base andpresenting a top surface that is convex upwardly, members ofnon-conductive refractory material providing Walls which with the convextop surface of the electrode form a relatively long and narrowcharge-receiving space extending longitudinally of the electrode, andmeans supporting the refractory members in place; and a second electrodemovable longitudinally of the first electrode to progressively fuse thecharge.

6. In a rod forming device of the character described, a mould adaptedto receive a charge of fusible ingredients and including a centrallongitudinally disposed electrode forming the bottom of said mould andside members of refractory non-conductive material forming opposedwalls,

and with the electrode forming a relatively long narrow charge receivingspace extending longitudinally of the electrode, said electrode having across-sectional area several times greater than that of the rod to beproduced, and a second electrode movable longitudinally of the firstelectrode to progressively melt the charge.

7. A device as described in claim 6 in which

